232 



Bulletin 193. 



Yi- 





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face. Sometimes, even in this earlj stage, shrinkage of the wood 

 will have taken place. If not very marked when freshly cut from 

 the wood, the shrinkage of tlie wood on drying, marks it off in a 



beautiful manner, by fine lines and 

 holes into cuboideal areas. 



In many of these cases of the 

 heart rot of trees, after the heart 

 wood is well affected, the mycelium 

 being well established and vigorous, 

 gradually encroaches on the cam- 

 bium or living area beneath the 

 bark. In this way, many of the 

 branches in the top of the tree die, 

 and in some cases later the cam- 

 bium of tlie trunk may be so de- 

 stroved as to kill the tree outrio^ht. 

 Tlie red spruce example, in the 

 Adirondack woods, was a tree of 

 handsome proportions near Pearce- 

 held Falls, in the Eaquette River, 

 left bv the lumberman a few vears 

 prior to 1896, the season when I 

 observed the tree. At some dis- 

 tance there was no indication that 

 the tree was diseased and I enquired 

 of my guide, who had at one 

 time some experience in cutting 

 timber, why the tree was left. 

 " That tree ain't no good," he re- 

 plied. As we approached nearer, 

 he said, "don't you see the gum 

 running from all the knot holes ? " 

 This he explained was regarded as 

 a sure sio^n of "heart rot." Fur- 

 thermore the tree was "checked" 

 on one side, the crack being quite large and extending for some dis- 

 tance. The check was probably caused by a wrench given tlie 

 weakened tree during a heavy wind. There was no. other external 



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62. — Effect on wood of red spruce 

 by the mycelium of Poly- 

 poms horealis. 



